Evolution of angiographic restenosis rate and late lumen loss after intracoronary beta radiation for in-stent restenotic lesions

Association of increased serum CTRP5 levels with in-stent restenosis after coronary drug-eluting stent implantation: CTRP5 promoting inflammation, migration and proliferation in vascular smooth muscle cells

BACKGROUND

We investigated whether serum level of C1q/TNF-related protein (CTRP) 5 is associated with in-stent restenosis (ISR) after percutaneous coronary intervention (PCI) with drug-eluting stent (DES) implantation, and assessed the biological effects of CTRP5 in human aortic smooth muscle cells (hASMCs).

METHODS AND RESULTS

Serum CTRP5 levels were assayed in 306 patients with and 306 patients without angiographic ISR at approximately one year after DES-based PCI. Multivariate logistic regression analysis was performed to determine risk factors for ISR. Notably, serum CTRP5 levels were higher in ISR patients than in non-ISR counterparts (197±84ng/mL vs. 150±74ng/mL, P<0.001). Compared with the lowest tertile (<125ng/mL) of CTRP5, patients with the mid (125-200ng/mL) and the highest tertile (>200ng/mL) of CTRP5 had a more than 1.6-fold (adjusted OR=1.670-2.127, P≤0.039) and 7.4-fold (adjusted OR=7.478-11.264, all P<0.001) increased risk of ISR (all P for trend <0.001), respectively, after adjustment for potential clinical, biochemical and angiographic characteristics. To assess the biological effects of CTRP5, we stimulated hASMCs with this protein. CTRP5 concentration-dependently induced the expression of MMP-2, cyclin D1 and TNF-α in hASMCs, with activation of Notch1, TGF-β and hedgehog signaling pathways. Consistently, this protein promoted migration and proliferation of hASMCs in wound-healing, Boyden chamber and Brdu incorporation assay.

CONCLUSION

Increased serum CTRP5 level is associated with ISR after PCI with DES implantation. CTRP5 promotes proliferation, inflammation and migration in vascular smooth muscle cells through activation of multiple pathways.

Increased glycated albumin and decreased esRAGE concentrations are associated with in-stent restenosis in Chinese diabetic patients

BACKGROUND

We investigated the impact of glycated albumin (GA) and endogenous secretory receptor for advanced glycation end products (esRAGE) and RAGE polymorphisms on occurrence of in-stent restenosis (ISR) in Chinese patients with type 2 diabetes.

METHODS

Four hundred nineteen patients with diabetes were divided, based upon the presence or absence of coronary artery disease (CAD) and ISR, into Group I (205 patients without CAD), Group II (128 patients with CAD but without ISR) and Group III (86 patients with ISR). One hundred fifty-two normal subjects were served as controls. Serum concentrations of GA and esRAGE were measured, and RAGE polymorphisms (-374T>A, -429T>C and G82S) were analyzed.

RESULTS

Serum GA concentration was higher and, in contrast, esRAGE concentration was lower in Group III than in the other groups (P<0.05). These two protein concentrations correlated closely with loss index (all P<0.01), and were independent risk factors for ISR in diabetic patients (P=0.01 and P=0.025, respectively). However, there were no differences in the allele and genotype frequencies in the 3 polymorphisms of RAGE gene between groups.

CONCLUSIONS

Increased GA and decreased esRAGE concentrations, but not -374T>A, -429T>C and Gly82Ser polymorphisms of RAGE gene, are associated with ISR in Chinese patients with type 2 diabetes.

Acute lumen overdilation improves outcome after brachytherapy of in-stent restenosis

BACKGROUND

The aim of our study was to test the impact of acute lumen overdilation on neointimal hyperplasia and late lumen size after vascular brachytherapy for in-stent restenosis (ISR).

METHODS

Forty-seven ISR lesions located in 47 coronary arteries in 44 consecutive patients underwent beta brachytherapy with serial intravascular ultrasound studies. Vessel, lumen, and stent cross-sectional area were measured at 1-mm steps. Based on an interpolated reference cross-sectional area, each cross section was assessed as overdilated (lumen cross-sectional area>interpolated reference cross-sectional area) or not overdilated (lumen cross-sectional area <interpolated reference cross-sectional area).

RESULTS

Overall, 502 sections were overdilated and 673 sections were not. Overdilated sections had a larger final lumen cross-sectional area (8.02+/-1.98 vs. 6.90+/-2.23 mm2, P<.001) and more recurrent neointimal hyperplasia (1.59+/-2.17 vs. 0.31+/-1.79 mm2, P<.001), but a smaller follow-up area stenosis (-1.03+/-32.99% vs. 22.15+/-20.75%, P<.001). This was especially true in smaller arteries (angiographic reference<3.0 mm) where larger follow-up lumen cross-sectional area and a corresponding smaller area stenosis were present (5.38+/-1.98 vs. 4.84+/-1.88 mm2 and 6.90+/-31.57% vs. 28.61+/-21.86%, P<.01 and P<.001, respectively).

CONCLUSIONS

Especially in small arteries, the strategy of acute lumen overdilation during balloon angioplasty prior to beta vascular brachytherapy treatment of ISR lesions has a favorable long-term result.

Optimization of dose prescription protocol and its impact on delivered dose and vascular response after beta-radiation for in-stent restenosis. A randomized trial with serial volumetric intravascular ultrasound and dose volume histograms

AIM

The incidence of restenosis within stented segment after intravascular brachytherapy with recommended dose prescription protocols is up to 25%. Therefore, we designed a randomized trial comparing recommended dose prescription protocol with dosing adjusted for the source-to-target distance.

METHODS

Fifty-one in-stent restenosis (ISR) lesions in 48 patients underwent centered source beta-irradiation with serial intravascular ultrasound. Patients randomly received 20 Gy at 1 mm either beyond lumen surface [n=25, standard group (S)] or external elastic membrane [n=26, dosing-adjusted (DA) group]. Minimum dose absorbed by 90% of adventitia (DV(90%Adv)) was calculated.

RESULTS

DV(90%Adv) was higher for the DA group than for the S group (21.63+/-5.67 vs. 12.05+/-4.88 Gy, P<.001). After 8.9+/-4.5 months there was complete lumen preservation in DA vs. lumen decrease subsequent to neointimal hyperplasia (NIH) in S group (0.10+/-1.20 vs. -0.61+/-1.29 mm3/mm, P<.05). Vessel volume increased significantly in the DA group and was unchanged in S group (+1.73, P=.002 vs. 0.14 mm3/mm, P=NS). DV(90%Adv) correlated inversely with NIH volume and positively with vessel volume change (r=-.405, P=.007 and r=.363, P=.017, respectively).

CONCLUSION

For beta-irradiation of ISR, dosing adjusted for the source-to-target distance leads to significant increase in target delivered doses, which is associated with complete NIH inhibition and induction of positive vessel remodeling.

Current understanding of coronary in-stent restenosis. Pathophysiology, clinical presentation, diagnostic work-up, and management

In-stent restenosis is the limiting entity following coronary stent implantation. It is associated with significant morbidity and cost and thus represents a major clinical and economical problem. Worldwide, approximately 250 000 in-stent restenotic lesions per year have to be dealt with. The pathophysiology of instent restenosis is multifactorial and comprises inflammation, smooth muscle cell migration and proliferation and extracellular matrix formation, all mediated by distinct molecular pathways. Instent restenosis has been recognised as very difficult to manage, with a repeat restenosis rate of 50% regardless of the mechanical angioplasty device used. Much more favourable results were reported for the adjunctive irradiation of the in-stent restenotic lesion, with a consistent reduction of the incidence of repeat in-stent restenosis by 50%. Data from the first clinical trials on drug-eluting stents for the treatment of in-stent restenosis have shown very much promise yielding this strategy likely to become the treatment of choice. This review outlines the histological and molecular findings of the pathophysiology, the epidemiology, the predictors and the diagnostic work-up of in-stent restenosis and puts emphasis on the various treatment options for its prevention and therapy.

Determinants of model of renarrowing after beta radiation for in-stent restenosis

It is unknown whether model of renarrowing after beta-radiation for in-stent restenosis (ISR) is influenced by the type of geographic miss (GM).

METHODS

In 166 ISR treated with Galileo, serial quantitative coronary angiographic analysis was done. Minimal lumen diameters and lengths were measured for (1) stent, (2) peri-stent subsegments subjected to angioplasty with/without irradiation, and (3) irradiation margins. GM was defined as: (Type 1) edge injury within the 32P source dose fall-off: 2.0 mm inside and outside the source end marker or (Type 2) overt, nonirradiated injury: beyond the outer 2.0-mm long dose fall-off zone.

RESULTS

Restenosis rate was 28.3% at 8.9+/-4.5 months with 60% located exclusively outside the stent. Type 1 GM was present in 24.7% of proximal edges, whereas Type 2 in 18.1%. Respective percentages for distal edges were 23.5% and 15.7%. Regardless of presence and type of GM, significant late lumen loss occurred only outside the stent. However, the biggest late lumen loss at the proximal edge was induced by the Type 1 GM (0.65+/-0.79, p<0.001), while proximal Type 2 GM was not associated with edge renarrowing (-0.04+/-0.48, p=NS). Both reference lumen diameter and proximal Type 1 GM influenced restenosis independently (OR 0.47; 95%CI 0.24-0.90; p=0.023 and OR 2.46; 95%CI 1.12-5.40; p=0.025).

CONCLUSIONS

Regardless of presence and type of geographic miss, late lumen loss after beta-radiation occurs only outside the stent. However, injury within the proximal 32P dose fall-off but not overt edge injury is associated with the biggest late lumen loss at the respective edge, triggering recurrent restenosis.

Three-year follow-up after intracoronary beta-radiation therapy for in-stent restenosis

BACKGROUND

Most studies that proved intracoronary radiation therapy (IRT) to be highly effective to reduce recurrent restenosis after treatment of in-stent restenosis (ISR) have looked at time periods up to 12 months. Whether the beneficial effect from radiation is sustained during long-term follow-up remains a concern. This study sought to evaluate the effectiveness of IRT using a beta-emitter during a 3-year follow-up period.

METHODS

One hundred twenty-eight consecutive symptomatic patients (mean age, 63 +/- 11 years) with 134 in-stent restenotic lesions were treated for ISR with IRT (noncentred beta-emitter, Novoste; radiation dosis 21.1 +/- 3.1 Gy). Six-month angiographic follow-up was obtained in 104 patients (81%) with 105 lesions (78%). All patients underwent 36-month clinical follow-up.

RESULTS

Six-month angiographic restenosis rate was 22% in stent (29% in lesion) with an in-stent late loss of 0.49 +/- 0.62 mm. Target lesion resvascularization (TLR) at 6-month follow-up was performed in 23 cases (18%). MACE (death, myocardial infarction, and target vessel revascularisation) was observed in 24 patients (19%). At 36-month follow-up, TLR increased to 36 cases (28%) and MACE was observed in 47 patients (37%). In a multivariate analysis, minimal lumen diameter before treatment of ISR using IRT was the only predictor of recurrent TLR at 36 months (OR = 0.131; 95% CI, 0.068-0.254; p = 0.002). In a subgroup of patients (N = 15) without restenosis at 6-month angiography but with clinically driven recurrent late angiography (mean, 18 +/- 7 months); in-lesion late loss increased from 0.47 +/- 0.54 mm at 6 months to 1.27 +/- 0.76 mm at repeated angiography (p = 0.005).

CONCLUSION

There is a considerable number of delayed recurrent restenosis post IRT for ISR. This is due to ongoing late loss more than 6-month post IRT. The minimal lumen diameter before IRT predicts the need for recurrent TLR at 36 months.

Three-year clinical follow-up after strontium-90/yttrium-90 beta-irradiation for the treatment of in-stent coronary restenosis

Because late vessel failure has been speculated as a possible limitation of vascular brachytherapy, we conducted a prospective clinical evaluation at 6, 12, 24, and 36 months of follow-up after irradiation with strontium-90/yttrium-90 for in-stent restenosis, regardless of the patient's symptomatic status. We report complete 3-year follow-up data for 106 consecutive patients. The cumulative rate of death at 6, 12, 24, and 36 months was 0.9%, 0.9%, 0.9%, and 1.9% respectively. The corresponding rates for acute ST-elevation myocardial infarction were 2.8%, 4.7%, 4.7%, and 4.7%, respectively. The cumulative rate of late thrombotic occlusion at 6, 12, 24, and 36 months was 3.8%, 4.7%, 4.7%, and 4.7%, respectively. The corresponding rates of target lesion revascularization and target vessel revascularization were 8.5% and 12.3% (p = 0.046), 14.2% (p = 0.157) and 18.0% (p = 0.046), 12.3% and 18.9% (p = 0.008), and 21.7% (p = 0.083) and 29.2% (p = 0.005), respectively. The cumulative rate of all major adverse cardiovascular events at 6, 12, 24, and 36 months was 16.1%, 24.5% (p = 0.003), 27.4% (p = 0.083), and 35.8% (p = 0.003), respectively. In conclusion, these results indicate a delayed and, even in the third year after the index procedure, continued restenotic process after beta irradiation of in-stent restenotic lesions.

Early time course of neointima formation and vascular remodelling following percutaneous coronary intervention and vascular brachytherapy of in-stent restenotic lesions as assessed by intravascular ultrasound analysis

In-stent restenosis (ISR) represents the major limitation of stent implantation. Treatment, although of relative technical ease, is unsatisfactory due to a high incidence of recurrent restenosis. Vascular brachytherapy (VBT) has emerged as a powerful adjunct therapeutic modality to treat ISR. Inhibition of neointima formation has been regarded as the relevant mechanism of action. Yet, positive remodelling has been suspected as another contributing factor. Since only very few precise analyses of the extent, distribution and time course of the respective mechanims exist, the goal of the present study was to describe the changes of the vessel geometry at the target lesion and at the reference site following angioplasty and VBT of ISR in 42 patients by means of quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS) before and after the index procedure and at the 3 and 6 month follow-up. By QCA the acute lumen gain measured 2.2+/-0.8 mm, the late lumen loss at 3 months was 0.1+/-0.5 mm and at 6 months 0.4+/-0.7 mm. By IVUS luminal cross-sectional area increased from 1.5+/-1.2 mm(2) to 7.9+/-1.9 mm(2) (p<0.001). The intima hyperplasia cross-sectional area at 3 months was only 0.2+/-1.0 mm(2) (p=0.191), but increased to 0.7+/-0.6 mm(2) (p<0.001) at 6 months resulting in a lumen cross-sectional area of 7.1+/-1.7 mm(2). Stent dimensions did not show any significant changes over time. The external elastic membrane cross-sectional area at 3 months increased by 1.3+/-1.9 mm(2) (p<0.001), and showed a further increase by 0.7+/-2.9 mm(2) at 6 months. Positive remodelling could be demonstrated also at the reference segment. In conclusion the absolute amount of intima hyperplasia during a 6-month follow-up period after VBT of ISR is low and most pronounced between the third and sixth month. Besides this, predominantly within the first 3 months of follow-up, significant positive remodelling could be demonstrated at the target lesion and at the reference site. Both observed effects may contribute to the preservation of the vessel lumen.

Superiority of sirolimus eluting stent compared with intracoronary beta radiation for treatment of in-stent restenosis: a matched comparison

OBJECTIVE

To compare acute and follow up clinical and angiographic results after treatment of in-stent restenosis (ISR) by sirolimus eluting stents (SES) with results obtained after intracoronary radiation therapy (IRT).

DESIGN

Matched pair analysis.

METHODS

62 consecutive ISR lesions (< 30 mm lesion length, reference diameter < 3.5 mm) in 62 patients were treated with SES. From a database of 174 lesions (n = 141 patients) treated for ISR by intracoronary beta radiation, 62 lesions (62 patients) were pair matched with the SES group for diabetes mellitus, lesion length, vessel size, and pattern of ISR. Six month angiographic and 12 month clinical follow up results were obtained.

RESULTS

Baseline clinical and angiographic characteristics were similar between the groups (not significant). SES implantation resulted in significantly lower postprocedural in-lesion diameter stenosis than did IRT (mean (SD) 14.2 (9.5)% v 21.1 (10.6)%, p = 0.001), significantly higher minimum lumen diameter at follow up (1.91 (0.58) v 1.55 (0.72) mm, p = 0.005), and a higher net gain (1.16 (0.55) v 0.77 (0.70) mm, p = 0.002). Angiographic binary in-lesion restenosis rate at six months was 11% in the SES group and 29% in the IRT group (p = 0.046). In 16 ISR lesions SES were used after failed IRT and in 46 lesions for first time ISR. In-lesion late loss was higher after use of SES for failed IRT than after use of SES for first time ISR (0.61 (0.67) mm v 0.24 (0.41) mm, p = 0.018). In a multivariate analysis prior failed IRT was the only independent predictor for recurrent restenosis after SES for ISR (p = 0.052, odds ratio 5.8). Six patients (10%) in the SES group and 17 patients (27%) in the IRT group underwent target lesion revascularisation during the 12 months of follow up (p = 0.022).

CONCLUSIONS

In this non-randomised matched cohort SES achieved acute and follow up results superior to IRT for treatment of ISR even if cases of failed IRT are included. Failed IRT is a predictor of impaired SES effectiveness.

Vascular restenosis - striving for therapy

Restenosis is the limiting entity following coronary angioplasty. It is associated with significant morbidity, mortality and cost, and thus represents a major clinical and economical problem. Despite technical improvements, restenosis after conventional balloon angioplasty occurs in 30 - 60% of cases. Coronary stenting was able to reduce the incidence by approximately 30%; nevertheless, some 250,000 patients experience in-stent restenotic lesions/year worldwide. In-stent restenosis has been recognised as very difficult to manage, with a repeat restenosis rate of 50%, regardless of the angioplasty device used. So far, only vascular brachytherapy has convincingly reduced the incidence of repeat in-stent restenosis (by 50%) and thus, has emerged as the gold standard of therapy. The introduction of drug-eluting stents has shown a great deal of promise for the treatment of both de novo and restenotic lesions, with reported restenosis rates of < 10%, and benefit for virtually all patient subsets at a higher risk of restenosis. This review outlines the pathophysiology, epidemiology and predictors of the restenosis process, and places emphasis on the various treatment options for its prevention and therapy.

Predictors of 32P beta brachytherapy failure in patients with high-risk in-stent restenosis

BACKGROUND

The effectiveness of coronary radiation therapy for the treatment of in-stent restenosis (ISR) has been established in several randomized clinical trials. The efficacy of this treatment in the general population is less well established.

METHODS AND MATERIALS

We report our experience in 118 consecutive patients with nonselected high-risk ISR who had undergone successful percutaneous coronary intervention and brachytherapy with (32)P beta-irradiation and who were prospectively enrolled in a quantitative angiographic and clinical follow-up protocol at 7 months after the index procedure. The aim of this study was to investigate the independent predictor of angiographic restenosis after (32)P brachytherapy treatment.

RESULTS

Of the patients, 28.8% were diabetics. The mean lesion and mean radiated lengths were, respectively, 30.1 +/- 17.2 and 43.8 +/- 16.9 mm. The ISR pattern was diffuse in 96% of the treated lesions; in particular, 22.1% presented an occlusive pattern and 37.1% a proliferative pattern. At follow-up angiographic, restenosis and major adverse cardiac events (MACE) rates were, respectively, 20.8% and 29.6%. The univariate predictors of angiographic restenosis were procedural geographic miss, pattern IV ISR, manual pullback maneuver of the radiation source, preprocedural lesion percentage stenosis and preprocedural lesion MLD. At logistic regression analysis, only geographic miss and pattern IV ISR were independent predictors of post intracoronary radiation therapy (IRT) angiographic restenosis.

CONCLUSION

These data indicate that 7-month angiographic restenosis after (32)P IRT in complex patients with ISR is not a frequent event and is predicted mainly by an occlusive lesion at baseline and by procedural geographical miss.